Tank construction



March 9, 1954 H. H. HENDON ET AL 2,671,573

TANK CONSTRUCTION Filed Sept. 28, 1949 2 Sheets-Sheet l INVENToR. How/mo .4. ww @AWA/v meer H. #EA/00N March 9, 1954 HENDON ET AL 2,671,573

TANK CONSTRUCTION Filed Sept. 28, 1949 2 Sheets-Sheet 2 INVENTOR Home@ n. vm oem/v #meer fl. #5A/DON ATTORNEYS Patented Mar. 9, 1954 TANK CONSTRUCTION Harry H. Hendon and Howard A. Van Orman, Birmingham, Ala., assignors to Knock Down Tanks Inc., a corporation of Alabama Application September 28, 1949, Serial No. 118,228

1 Claim. l

This invention relates t0 metal septic tank for the disposal of sewage, and is o1" the general type described in our pending application Serial Number 85,912, filed April 6, 1949, now Patent No. 2,553,885, dated May 22, 1951.

The principal object of our invention is to provide a septic tank which shall be constructed in sections capable of being nested together to occupy a relatively small space in storage and shipping, and which may be readily assembled and installed.

Another object is to provide a sectional septic tank wherein the sections are adapted to be nested and occupy little space in storage and shipping and which shall include a simple, fiuid tight joint between the sections.

A further object is to provide a sectional septic tank which may include at least one removable baille and in which the sections may be nested together for shipping with the baille removed from its operating position, together with means to hold the sections and baiile against shifting during shipment, and to hold the baffle in position after assembly.

A still further object is to provide a sectional septic tank which shall have an integral top on the upper section, the top being provided with a clean out opening having a fluid tight cover therefor.

A further object is to provide a sectional metal septic tank the upper section of which shall be so constructed as to provide the maximum of strength with a minimum of weight.

A still further object is to provide a sectional metal septic tank of maximum strength and relatively light weight and which shall meet modern requirements set by health authorities for residential septic tanks.

As is well known in the art to which our invention relates, assembled metal septic tanks are bulky to handle and are of low weight relative to size. These characteristics present difculties in the manufacture and in the storage and shipping thereof and subject them to a relatively high freight rate. We have found by making such tanks in sections with the sections adapted to nest together, that appreciable economies in manufacture, storage and handling are obtained. Also, due to the lower frieght rate thus obtained, material savings in freight cost are realized. In order to adapt the sections for nesting, we make the upper section of the tank slightly smaller in its dimensions than the lower section so that the upper section may be inverted and nested into the lower section.

The upper section has sides which converge upwardly slightly when in the operating position. The sides of the upper portion are turned inwardly near the top at approximately a 45 angle to join a horizontal top. The upper section is provided with an outturned flange at its lower 'edge which is adapted to engage within an outwardly and upwardly turned stiiening flange along the upper edge of the lower section, thereby giving added strength to the tank. The flanges may be joined together by bolts to retain the sections in either the nested position or in the operating position. The ilanges, when the sections are in the operating position, form a groove around the tank which is filled with a bituminous or other suitable sealing material thus providing a fluid tight joint. A bituminous coating may be applied to both sections by hot dipping. The cover for the clean out opening is in place when the top section is dipped and is thereby sealed in place. This makes the erected tank fluid tight with the exception of the inlet and outlet connections.

A septic tank embodying features of our invention is illustrated in the accompanying drawing, forming a part of this application, in which:

Fig. l is a perspective view of an erected septic tank;

Fig. 2 is a longitudinal sectional view of an erected septic tank;

Fig. 3 is a transverse sectional view taken along line III-Ill of Fig. 2;

Fig. 4 is a transverse sectional view of a septic tank in the nested position; and,

Figs. 5 to 8 inclusive are detail sectional views showing various forms of joints which we may employ between the sections.

Referring now to the drawings for a better understanding of our invention, we show in Fig. 1 a rectangular septic tank comprising a lower section I and an upper section il. The lower section lil is provided with a bottom I2, sides I3 and ends i4. The upper section Il is provided with ends I6, an integral top Il having a manhole or clean out opening It therein and sides 2 I A cover I8' for the manhole is manually held in place by clips I9. The upper section is slightly shorter, slightly narrower, and slightly shallower than the lower section to provide for inverting and nesting the sections. The sides 2| of the upper section also converge inwardly toward the top to further aid in nesting. Near the top they are both turned inwardly at a 45 angle as shown at l5 and l5 to join the horizontal portion of the top ll. The horizontal top of the tank is from 1/2 to 3A the width of the tank at the point where the top portions oi the side walls turn inwardly. This forms a truss, or arch shaped top portion which provides greater resistance to the earth load on top of the tank when in use and also reduces the unsupported span at both the sides and the top.

The lower section lll of the tank is provided with an outwardly and upwardly turned flange 22 along its upper edge extending all around the section. The upper section Il is provided with an outwardly turned flange 23 extending all around the section along its lower edge, which is adapted to fit within the flange 22. The flanges may be joined together by bolts 24 to retain the sections in either the nested position, as shown in Fig. 4, or in the operating position as shown in Fig. 3. The flanges 22 and 23 give added strength to the tank and increased resistance to pressure due to packing earth around the tank when it is installed and to water pressure from within. We are thus enabled to provide a tank of the requisite strength with a minimum thickness of material and without additional reinforcing members.

The outwardly turned flange 23 on the upper section when in operating position, provides a sealing groove 29 as shown in Fig. 5 which extends all around the tank. This groove is illled with a suitable sealing material 27, for example, a bituminous material such as asphalt, or tar, to provide a fluid tight joint. Another form of joint is shown in Figs, 7 and 8 in which the bituminous material 21 is wiped into the flange 22 in a triangular shape in cross section. The upper section .of the tank is then set into position on the lower section and the flange 23' compresses the bituminous material between the two flanges of the joint on the side where it is subject to internal pressure. The flange 23 on the upper section is slightly downwardly inclined with respect to the horizontal as shown, and the flange 22 on the lower section is slightly upwardly inclined with respect to the horizontal as shown in Figs. 7 .and 8. The shape of the joint thus formed leaves a wedge shaped ring 25 of the compound on the inside of the joint which makes it permanently fluid tight. After the bolts 2d have been tightened the groove 25' above the flange 23 may be also filled with the sealing material 2`I' to further seal the tank and protect the bolts.

When the tank is constructed a bituminous coating may be applied to both sections thereof by hot dipping. Each half is submerged in a suitable heated vat of coating material. The open construction provides ready drainage of the excess coating material as the .sections are removed from the dipping vat. When the top section of l the tank is dipped in the coating compound the cover I8 for the clean out opening is thus sealed in place, and except for the inlet and outlet connections the erected tank is fluid tight. The upper section II of the tank is provided with the usual inlet opening 28, at one end and an outlet opening 29 at the opposite end. The inlet connection 28 and outlet connection 29 are made flush with the outside of the tank so as not to interfere with the nesting of the sections. Inwardly of the opening 28 is an inlet baille 3l and inwardly of the opening 29 is an outlet baiile 32, both being typical in construction and are welded into the top section of the tank.

Sectionalizing baiiles 33a and 33o may be provided across the tank by welding the upper baille 33a in place in the upper section of the tank and fastening the lower baille 33h to the lower section of the tank by means of a metal hinge or clip 34. When the tank is in the nested position as shown in Fig. 4, the lower baille 33h is lying on the tank bottom. When the tank is erected the lower bafile 33D is raised to a vertical position and is held in that position by metal clips 36 which have one end welded to the walls of the lower section I0. The upper and lower bailles are spaced apart sufficiently, as shown, to permit the passage of liquid thereby. Also, the lower baille 33h may have a portion removed at the bottom, such as shown at to provide drainage thereby.

Sewage is introduced into the upper section I l of the tank through the inlet connection 28 and is directed downwardly by the inlet baille 3 I. Liquid flows out under the outlet baille 32 and outlet 29 to the soil disposal area, as is well understood.

As shown in Fig. 4 of the drawings, section I I is inverted from the position shown in Fig. 3 when nesting the sections for storage and shipping and is inserted within the section I0. The dimensions of section I I are suiliciently less than those of section I0 so that it lits readily within section I0.

From the foregoing, it will be apparent that we have devised an improved tank construction which is simple of design, economical of manufacture, having the maximum of strength, with a minimum of weight and one which may be packaged for handling and shipping so as to occupy relatively small spaces in storage and shipping, thereby greatly reducing cost of handling and the freight rates applicable to its shipment.

Throughout this specification we have described the upper section of our improved tank as being smaller than, and nesting within, the

' lower section. We wish it understood however that this is for convenience of description only, as it may be constructed for the lower section to be nested within the upper.

While we have shown our invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and we desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claim.

What we claim is:

A rectangular metal septic tank comprising a lower section, an upper section having an inlet and an outlet and having slightly smaller dimensions than the lower section whereby when inverted it is adapted to nest within the lower section, a reinforcing ilange extending around the upper edge of the lower section inclined slightly upwardly from the horizontal and terminating in a vertically extending portion, and a reinforcing flange extending around the lower edge of the upper section inclined slightly downwardly from the horizontal and engaging the upper surface of the slightly upwardly inclined flange on the lower section and forming a wedge shaped groove extending around inside of the joint and a groove extending around the outside of the joint, and bituminous sealing material in said grooves.

HARRY H. HENDON. HOWARD A. VAN ORMAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 643,787 Brochu Feb. 20, 1900 1,376,216 Mittinger Apr. 26, 1921 1,432,075 Mallu Oct. 17, 1922 1,451,967 Starclough Apr. 17, 1923 1,866,979 Lerio July 12, 1932 2,091,731 Gredell Aug. 31, 1937 2,134,678 Billig et al. Oct. 25, 1938 2,219,289 Bennett Oct. 29, 1940 2,233,093 Carman et al. Feb. 25, 1941 2,300,259 Kueppers Oct. 17, 1942 FOREIGN PATENTS Number Country Date 544,533 France June 23, 1922 

